[英]Ionic 2: access main page's services from popover callback
我使用angularJs已经有一段时间了,我刚刚切换到angular2。我正在从页面调用弹出窗口,当从弹出窗口中选择一个项目时,我应该从api中获取一些数据。 我遇到的问题是,当我使用“ this”时,它不再引用Vendor上下文,因此无法访问VendorServices函数。 有没有一种方法可以引用父类(调用弹出窗口的页面),以便获取所有变量?
import { Component } from '@angular/core';
import { VendorService} from '../vendors/services'
import { NavController, NavParams } from 'ionic-angular';
import { Meals } from '../meals/meals';
import { PopoverController } from 'ionic-angular';
import { LocationsPopover } from '../locations-popover/locations-popover';
@Component({
selector: 'vendors',
templateUrl: 'vendors.html'
})
export class Vendors {
mealsPage = Meals;
public locationName: string;
vendors: any;
selectedLocation:String;
constructor(public navCtrl: NavController, public params:NavParams, private vendorService:VendorService, public popoverController: PopoverController) {
this.locationName = params.get('location');
}
这是处理弹出框的函数:
showLocationsDropdown(event){
console.log("locations");
let popover = this.popoverController.create(LocationsPopover,{
cb:function(location){
this.selectedLocation = location.location_name;
console.log("selectedLocation", location.location_name);
// this.vendorService.getVendorsByLocationId(location.id).subscribe(
this.vendorService.getVendors().subscribe(
results=>{
console.log(results);
this.vendors = results;
}
);
}
});
popover.present({
ev:event
});
}
如果像这样使用function(location){
,则this
函数内部this
的封闭范围将是函数“实例”。 你可以这样做(location)=>{
访问词法this
showLocationsDropdown(event){
console.log("locations");
let popover = this.popoverController.create(LocationsPopover,{
cb:(location)=>{
this.selectedLocation = location.location_name;
或以旧方式将词法this
分配给变量(如self
),如果您不想在函数内丢失this
,请使用该变量
showLocationsDropdown(event){
console.log("locations");
var self = this; //<-- assign here
let popover = this.popoverController.create(LocationsPopover,{
cb:function(location){
self.selectedLocation = location.location_name; //<-- use here
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